• If you like what you see here and your interests are compatible with our 30,000 other users, Welcome. Fill out the registration form with your interests, your real name (seen only by moderators) and your city, state or country. Be certain that you have spelled your email address correctly! Your account is then manually checked and approved.

Wanted: McDonald ML

Darryl

Registered
We’re in the big league with this engine ! The bore is badly scored because somebody forgot to put the wear buttons back in the guidon pin ends but I’m not too concerned because the marks are behind the ports and it can’t start to make compression until the ports are closed anyway. I found an ML cylinder liner but , at this stage I don’t know if they’re the same. The main bearings are perfect and the big end is to. The rings look really good.Ian is sending me a hot bowl so all good at this stage
.3C422C9E-939A-43BE-B7B3-CC90E6E50ADC.jpeg23D91F76-87C5-4601-8ED0-FE193D730F59.jpeg6734D3B3-5750-47F3-A953-6813FBB7CAE9.jpeg

07C8BA16-1C50-4167-ACCE-B9128B6BF349.jpeg
 
how does it scavenge ? won't it affect the return pressure of the crankcase....
Anyhow if its a flanged liner, they can be made if the other one doesn't fit.
 

Darryl

Registered
how does it scavenge ? won't it affect the return pressure of the crankcase....
Anyhow if its a flanged liner, they can be made if the other one doesn't fit.
It will scavenge because of the shear volume of air displaced by the piston. There just won’t be enough time for much air to by-pass via the wear grooves. It’s not ideal but it will work. If the ML liner is different then I’ll just hone the M’s bore and she’ll be right.
 

isandian

Registered
I took a lot of photos at the Bookham sale and did not see that engine. The only McDonalds I saw were a TWB tractor, and P and J type engines. I bought the P, the main reason I was there. I do think an M would have jumped out at me and demanded I take its photo. Perhaps it was sold in the previous tender sale.
 

Darryl

Registered
You'd be right Ian. If it was there you would notice it. That is just what the bloke who loaded it said and he said it came from a saw mill too. I thought at the time that if it was from the Bookham sale, how would he know it was a saw mill engine also ?
Either way does not worry me anyway.
 

Wayne Timms

Subscriber
Last Subscription Date
06/09/2020
I took a lot of photos at the Bookham sale and did not see that engine. The only McDonalds I saw were a TWB tractor, and P and J type engines. I bought the P, the main reason I was there. I do think an M would have jumped out at me and demanded I take its photo. Perhaps it was sold in the previous tender sale.
Hi,
When Robinsons Bros had a property outside of Bendigo in the 70s, they had a McDonald M which my father took an interest in, but didn't buy. I remember the engine well as they had a coin sitting on the head and when the engine was running they would stand the coin on its edge. It would stay standing. It was sitting on a concrete bed. I recall the brother said that if he didn't get the price he wanted he would move it to Bookham. From memory it had come from a sawmill, I am not saying it is the same engine - but they did have one.
I have looked through my photos and I don't have photos of the M. I know there are photos of it....one of my brothers must have them.
Wayne
 

isandian

Registered
Boy! Those sure are scores in the bore. As you said, it won't make a lot of difference to it running. You can see where the locating tabs for the aluminium wear pads fit at the end of the gudgeon pins. I have made replacements by turning aluminium pads with a shoulder with a firm fit into the bore of the pin, and not worrying about location. The only thing to remember is to include a hole in one of them so you can drive the one on the other side out with a drift.
I am trying to remember how I got the head and piston off my ML. I would not dream of trying to lift them now without lifting aids.
 

isandian

Registered
Hi,
When Robinsons Bros had a property outside of Bendigo in the 70s, they had a McDonald M which my father took an interest in, but didn't buy. I remember the engine well as they had a coin sitting on the head and when the engine was running they would stand the coin on its edge. It would stay standing. It was sitting on a concrete bed. I recall the brother said that if he didn't get the price he wanted he would move it to Bookham. From memory it had come from a sawmill, I am not saying it is the same engine - but they did have one.
I have looked through my photos and I don't have photos of the M. I know there are photos of it....one of my brothers must have them.
Wayne
Wayne, I did not know Robinsons had a property near Bendigo. All of this points to Darryl's engine being one and the same, so at least some of its history can be put to bed. It must have been a substantial concrete footing to have a coin sitting on its end when running - they are not the best balanced engines in the world! When you or your father saw it running mounted on a concrete bed, was this still in the sawmill?
 

Wayne Timms

Subscriber
Last Subscription Date
06/09/2020
Hi,
No, the engine was not in a working sawmill when I saw it running. It was setup on the property not too far from the house. It was actually out in the open. I cannot remember if it was bolted directly to a concrete foundation or to a metal subframe which was then bolted to a concrete foundation.
Wayne
 

Darryl

Registered
M169. 1939 and only 63 M units ever produced, so pretty rare really. Cleaned up the Manzel lubricator today and half made the sight glass from Perspex . Haven’t done it yet for this one, but super glued the ends on the sight glass for my TL and it’s lasted years.
Also, the steel base is factory McDonald as they were shipped out all set up on the base with the out rigger bearing set
properly because of earlier crank failures. Forgot to say, I use a heat gun to bend the Perspex and make sure the steel bits are parallel , then cool it with water.
15E9C64C-650B-4862-899D-DFE278029AFC.jpeg03E48C03-8610-4020-8615-8C9F911EAF4B.jpeg46335AD6-24E0-4233-BC33-6904816101C1.jpegBACF12E8-6CAA-47EA-B590-03AF3FC936B5.jpeg7DB3AFB5-FD79-4795-B73A-0684B2BE7869.jpegF4A58A8E-1098-46E6-85A4-856A91F51C49.jpeg
 
Last edited:

Darryl

Registered
The piston bronze bushes are a bit worn so I will try to source something off the shelf to replace them ( od 3.250“ I’d 3” length 1.750”) Ian, did you ever need bushes?
 

isandian

Registered
My ML was in good condition when I obtained it, except missing the head. How much wear is in the bushes in yours? My TL that came out of a sawmill had wear right through the bronze, over 1/8" wear, yet it ran with no noise until you accelerated, then it let you know. If you are going to use it to pump water, then you probably need them to be in reasonable condition.
On my TL I found the oil hole to the gudgeon on top of the piston was blocked with carbon, so no oil was reaching the little end at all. I robbed the piston out of a second engine to replace it instead of making new bushes.
 
A engine machine shop will be able to fit and hone to size, if you have a lathe and can make bushes you can also get the fit correct by using a adjustable reamer, i should add you need a pilot with the reamer so both bush bores are in alignment as well as having a good fit.
Machining to a close to size then Honing is the standard procedure to get a accurate size in a engine shop.
 
Last edited:

Darryl

Registered
Sight glass came out not too bad. I put a few scratches in it with the cutoff blade.
The bushes would have 30 thou clearance if not more, not the end of the world but I'll fix it while its apart.
20200706_164951.jpg20200706_164934.jpg
 

isandian

Registered
30 thou is certainly not the end of the world in these engines. Don't make the new ones too tight in case they bind when hot. You may never place it under enough load to get the top of the piston really hot, but in service this can happen.
 

Top